Methods will be improved for the extraction and purification of proteoglycans from dermis. The chemical nature and physical interactions of the products will be studied, especially with regard to binding to hyaluronic acid (by analogy with the molecular phenomena found in cartilage). Antibodies to skin proteoglycans will be prepared, and their immunological relationships will be compared to those of cartilage. Changes in the quantity and nature of the proteoglycans will be correlated with aging or physiological state.